Simplify internal lifecycle of Peripheral (#491)

Author: twyatt

core/src/appleMain/kotlin/CentralManager.kt

@@ -2,6 +2,7 @@ package com.juul.kable
 
 import com.benasher44.uuid.Uuid
 import com.juul.kable.logs.Logging
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.withContext
 import platform.CoreBluetooth.CBCentralManager
@@ -49,20 +50,20 @@ public class CentralManager internal constructor() {
             .firstOrNull() as? CBPeripheral
 
     internal suspend fun connectPeripheral(
+        scope: CoroutineScope,
         peripheral: CBPeripheralCoreBluetoothPeripheral,
         characteristicChanges: MutableSharedFlow<ObservationEvent<NSData>>,
         logging: Logging,
         options: Map<Any?, *>? = null,
     ): Connection {
-        val parentCoroutineContext = peripheral.connectionScope.coroutineContext
         val cbPeripheral = peripheral.cbPeripheral
         val identifier = cbPeripheral.identifier.UUIDString
         val delegate = PeripheralDelegate(peripheral.canSendWriteWithoutResponse, characteristicChanges, logging, identifier)
         withContext(dispatcher) {
             cbPeripheral.delegate = delegate
             cbCentralManager.connectPeripheral(cbPeripheral, options)
         }
-        return Connection(parentCoroutineContext, delegate, logging, identifier)
+        return Connection(scope, delegate, logging, identifier)
     }
 
     internal suspend fun cancelPeripheralConnection(

core/src/appleMain/kotlin/Connection.kt

@@ -7,19 +7,22 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Deferred
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.async
-import kotlinx.coroutines.cancel
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
-import kotlin.coroutines.CoroutineContext
 
 internal class Connection(
-    parentCoroutineContext: CoroutineContext,
+    scope: CoroutineScope,
     val delegate: PeripheralDelegate,
     logging: Logging,
     identifier: String,
 ) {
 
-    private val scope = CoroutineScope(parentCoroutineContext + Job(parentCoroutineContext[Job]) + CoroutineName("Kable/Connection@$identifier"))
+    private val job = Job(scope.coroutineContext[Job]).apply {
+        invokeOnCompletion {
+            delegate.close()
+        }
+    }
+    val scope = CoroutineScope(scope.coroutineContext + job + CoroutineName("Kable/Connection/$identifier"))
 
     private val logger = Logger(logging, tag = "Kable/Connection", identifier = identifier)
 
@@ -59,9 +62,4 @@ internal class Connection(
         if (error != null) throw IOException(error.description, cause = null)
         response as T
     }
-
-    fun close() {
-        scope.cancel()
-        delegate.close()
-    }
 }

core/src/appleMain/kotlin/Peripheral.kt

@@ -28,7 +28,6 @@ import kotlinx.atomicfu.atomic
 import kotlinx.atomicfu.updateAndGet
 import kotlinx.coroutines.CoroutineName
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Job
 import kotlinx.coroutines.NonCancellable
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.flow.Flow
@@ -42,6 +41,7 @@ import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.onSubscription
 import kotlinx.coroutines.flow.updateAndGet
+import kotlinx.coroutines.isActive
 import kotlinx.coroutines.job
 import kotlinx.coroutines.sync.withLock
 import kotlinx.coroutines.withContext
@@ -109,9 +109,11 @@ internal class CBPeripheralCoreBluetoothPeripheral(
     private val logging: Logging,
 ) : CoreBluetoothPeripheral {
 
-    private val job = SupervisorJob(parentCoroutineContext.job) // todo: Disconnect/dispose CBPeripheral on completion?
-    private val scope = CoroutineScope(parentCoroutineContext + job + CoroutineName("Kable/Peripheral@${cbPeripheral.identifier.UUIDString}"))
-    internal val connectionScope = CoroutineScope(scope.coroutineContext + Job(scope.coroutineContext[Job]) + CoroutineName("Kable/Connect@${cbPeripheral.identifier.UUIDString}"))
+    private val scope = CoroutineScope(
+        parentCoroutineContext +
+            SupervisorJob(parentCoroutineContext.job) +
+            CoroutineName("Kable/Peripheral/${cbPeripheral.identifier.UUIDString}"),
+    )
 
     private val centralManager: CentralManager = CentralManager.Default
 
@@ -160,18 +162,11 @@ internal class CBPeripheralCoreBluetoothPeripheral(
 
     private val _connection = atomic<Connection?>(null)
     private val connection: Connection
-        inline get() = _connection.value ?: throw NotReadyException(toString())
+        inline get() = _connection.value?.takeIf { it.scope.isActive } ?: throw NotReadyException(toString())
 
     override val name: String? get() = cbPeripheral.name
 
-    private val connectAction = connectionScope.sharedRepeatableAction(::establishConnection)
-
-    private fun onDisconnected() {
-        logger.info { message = "Disconnected" }
-        connectAction.reset()
-        _connection.value?.close()
-        _connection.value = null
-    }
+    private val connectAction = scope.sharedRepeatableAction(::establishConnection)
 
     override suspend fun connect() {
         connectAction.await()
@@ -185,11 +180,15 @@ internal class CBPeripheralCoreBluetoothPeripheral(
         _state.value = State.Connecting.Bluetooth
 
         centralManager.delegate.onDisconnected.onEach { identifier ->
-            if (identifier == cbPeripheral.identifier) onDisconnected()
+            if (identifier == cbPeripheral.identifier) {
+                connectAction.reset()
+                logger.info { message = "Disconnected" }
+            }
         }.launchIn(scope)
 
         try {
             _connection.value = centralManager.connectPeripheral(
+                scope,
                 this@CBPeripheralCoreBluetoothPeripheral,
                 observers.characteristicChanges,
                 logging,
@@ -208,7 +207,6 @@ internal class CBPeripheralCoreBluetoothPeripheral(
             logger.error(e) { message = "Failed to connect" }
             withContext(NonCancellable) {
                 centralManager.cancelPeripheralConnection(cbPeripheral)
-                _connection.value = null
             }
             throw e
         }
@@ -224,7 +222,7 @@ internal class CBPeripheralCoreBluetoothPeripheral(
             withContext(NonCancellable) {
                 centralManager.cancelPeripheralConnection(cbPeripheral)
             }
-            onDisconnected()
+            logger.info { message = "Disconnected" }
         }
     }